Drew Marsh blogged about the talk given by my boss at this year's Microsoft Professional Developer's Conference (PDC) entitled What's New In System.Xml For Whidbey?". Since I'm directly responsible for some of the stuff mentioned in the talk I though it would make sense if I made some clarifications or added details where some where lacking from his coverage.

Usability Improvements (Beta 1)

  • CLR type accesors on XmlReader, XmlWriter and XPathNavigator: Double unitPrice = reader.ValueAsDouble


This was a big gripe from folks in v1.0 of the .NET Framework that they couldn't access the XML in a validated document as a typed value, this is no longer the case in Whidbey. However people who want this functionality will have to move to the XPathDocument instead of the XmlDocument. People will be able to get typed values from an XmlDocument (actually from anything that implements IXPathNavigable) but actually storing the data in the in-memory representation as a typed value will only be available on the XPathDocument.  


XPathDocument A Better XML DOM

"XmlDocument is dead."


  • XPathDocument replaces the XmlDocument as the primary XML store.
  • Feature Set
    • 20%-40% more performant for XSLT and Xquery
    • Editing capabilities through the XPathEditor (derives from XPathDocument) using an XmlWriter (the mythical XmlNodeWriter we've all been searching for).
    • XML schema validation
    • Strongly typed store. Integers stored as int internally (per schema) (Beta 1)
    • Change tracking at node level
    • UI databinding support to WinForms and ASP.NET controls (Beta 1)

Yup, in v1.0 of the .NET Framework we moved away from a push-based parser (SAX) in MSXML to a pull-based parser (XmlReader) in the .NET Framework. In v2.0 of the .NET Framework there's been a similar shift, from the DOM data model & tree based APIs for accessing XML to the XPath data model & cursor based APIs for accessing XML. If you are curious about some of the thinking that went into this decision you should take a look at my article in XML Journal entitled Can One Size Fit All? 


Note: XPathDocument2 in PDC bits will be XPathDocument once again by Beta 1. "We were at an unfortunate design stage at the point where the PDC bits were created."

Yeah, things were in flux for a while during our development process. The features of the class called XPathDocument2 in the PDC builds will be integrated back into the XPathDocument class that was in v1.0 of the .NET Framework.


The rest of the stuff in the talk (XQuery, new XML editor in Visual Studio.NET, ADO.NET with SQLXML, etc) isn't stuff I'm directly responsible for so I hesitate to comment further, however Drew has taken excellent notes about them so it is clear which direction we're going in for Whidbey.